U.S. patent application number 13/519850 was filed with the patent office on 2012-11-15 for method for receiving information on peripheral legacy base station in terminal of legacy support mode.
This patent application is currently assigned to LG ELECTRONICS INC.. Invention is credited to In Uk Jung, Yong Ho Kim, Ki Seon Ryu.
Application Number | 20120287884 13/519850 |
Document ID | / |
Family ID | 44227035 |
Filed Date | 2012-11-15 |
United States Patent
Application |
20120287884 |
Kind Code |
A1 |
Jung; In Uk ; et
al. |
November 15, 2012 |
METHOD FOR RECEIVING INFORMATION ON PERIPHERAL LEGACY BASE STATION
IN TERMINAL OF LEGACY SUPPORT MODE
Abstract
The present invention relates to a broadband wireless access
system, and more particularly, to a method for an advanced mobile
station to efficiently obtain information on a peripheral legacy
base station in a mobile communication system in which a legacy
system and an advanced system coexist. According to one embodiment
of the present invention, the present invention provides a method
for a mobile station to receive information on a peripheral base
station from a serving base station that operates in a mixed mode
in the mobile communication system in which the legacy system and
the advanced system coexist, and the method comprises the steps of:
receiving a second message that includes first time information for
indicating a time when a first message is broadcasted, in a first
region for the legacy system of the serving base station through a
second region for the advanced system of the serving base station,
and receiving the first message from the first region by using the
first time information.
Inventors: |
Jung; In Uk; (Anyang-si,
KR) ; Kim; Yong Ho; (Anyang-si, KR) ; Ryu; Ki
Seon; (Anyang-si, KR) |
Assignee: |
LG ELECTRONICS INC.
Seoul
KR
|
Family ID: |
44227035 |
Appl. No.: |
13/519850 |
Filed: |
December 29, 2010 |
PCT Filed: |
December 29, 2010 |
PCT NO: |
PCT/KR2010/009482 |
371 Date: |
June 28, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61290870 |
Dec 29, 2009 |
|
|
|
Current U.S.
Class: |
370/329 ;
370/328 |
Current CPC
Class: |
H04W 48/10 20130101 |
Class at
Publication: |
370/329 ;
370/328 |
International
Class: |
H04W 72/04 20090101
H04W072/04; H04W 4/00 20090101 H04W004/00 |
Claims
1. A method of receiving information on a neighbor base station,
which is received by an advanced mobile station (AMS) from a
serving base station operating in a mixed mode in a mobile
communication system having a legacy system and an advanced system
coexist therein, comprising the steps of: receiving a 2.sup.nd
message including a 1.sup.st time information indicating a time of
broadcasting a 1.sup.st message from a 1.sup.st zone for the legacy
system of the serving base station via a 2.sup.nd zone for the
legacy system of the serving base station; and receiving the
1.sup.st message from the 1.sup.st zone using the 1.sup.st time
information, wherein the 1.sup.st message includes system
information on at least one of a base station supporting the legacy
system around the serving base station and the 1.sup.st zone of a
base station operating in the mixed mode around the serving base
station.
2. The method of claim 1, wherein the 1.sup.st time information
comprises at least one selected from the group consisting of an
offset information indicating the time of broadcasting the 1.sup.st
message from the 1.sup.st zone as an offset from a time of
receiving the 2.sup.nd message and an interval information
indicating an interval of broadcasting the 1.sup.st message from
the 1.sup.st zone.
3. The method of claim 2, wherein each of the offset information
and the interval information is determined by a frame unit.
4. The method of claim 3, wherein the 1.sup.st message further
includes a 2.sup.nd time information indicating a time of
transmitting the system information of the 1.sup.st zone and
wherein the method further comprises the step of receiving the
system information of the 1.sup.st zone using the 2.sup.nd time
information.
5. The method of claim 1, wherein the legacy system comprises
WirelessMAN-OFDMA R1 reference system, wherein the advanced system
comprises IEEE 802.16m system, wherein the 1.sup.st message
comprises a neighbor advertisement (MOB_NBR-ADV0 message, and
wherein the 2.sup.nd message comprises an advanced neighbor
advertisement (AAI_NBR-ADV) message.
6. A mobile station device, which receives information on a
neighbor base station from a serving base station operating in a
mixed mode in a mobile communication system having a legacy system
and an advanced system coexist therein, comprising: a processor;
and a radio communication (RF) module configured to transceive
radio signals with the serving base station under control of the
processor, wherein the processor controls the radio communication
(RF) module to receive a 2.sup.nd message including a 1.sup.st time
information indicating a time of broadcasting a 1.sup.st message
from a 1.sup.st zone for the legacy system of the serving base
station via a 2.sup.nd zone for the legacy system of the serving
base station, wherein the processor controls the radio
communication (RF) module to receive the 1.sup.st message from the
1.sup.st zone using the 1.sup.st time information, and wherein the
1.sup.st message includes system information on at least one of a
base station supporting the legacy system around the serving base
station and the 1.sup.st zone of a base station operating in the
mixed mode around the serving base station.
7. The mobile station device of claim 6, wherein the 1.sup.st time
information comprises at least one selected from the group
consisting of an offset information indicating the time of
broadcasting the 1.sup.st message from the 1.sup.st zone as an
offset from a time of receiving the 2.sup.nd message and an
interval information indicating an interval of broadcasting the
1.sup.st message from the 1.sup.st zone.
8. The mobile station device of claim 7, wherein each of the offset
information and the interval information is determined by a frame
unit.
9. The mobile station device of claim 8, wherein the 1.sup.st
message further includes a 2.sup.nd time information indicating a
time of transmitting the system information of the 1.sup.st zone
and wherein the processor controls the system information of the
1.sup.st zone to be received using the 2.sup.nd time
information.
10. The mobile station device of claim 6, wherein the legacy system
comprises WirelessMAN-OFDMA R1 reference system, wherein the
advanced system comprises IEEE 802.16m system, wherein the 1.sup.st
message comprises a neighbor advertisement (MOB_NBR-ADV0 message,
and wherein the 2.sup.nd message comprises an advanced neighbor
advertisement (AAI_NBR-ADV) message.
11. A method of receiving a neighbor base station information,
which is received by an advanced mobile station (AMS) from a
serving advanced base station (ABS) in a broadband wireless access
system, comprising the steps of: transmitting a 1.sup.st message
including a base station type information to the serving advanced
base station; and receiving a 2.sup.nd message including the
neighbor base station information of a type indicated by the base
station type information from the serving advanced base station in
response to the 1.sup.st message.
12. The method of claim 11, wherein the base station type
information is set to a value indicating one selected from the
group consisting of a closed subscriber group-closed femto base
station (CSG-Closed Femto ABS), a closed subscriber group-open
femto base station (CSG-Open Femto ABS) and an open subscriber
group femto base station (OSG Femto ABS).
13. The method of claim 12, wherein the 1.sup.st message comprises
a scan reporting (AAI_SCN-REP) message and wherein the 2.sup.nd
message comprises a neighbor advertisement (AAI_NBR-ADV) message
transmitted by unicast.
14. A mobile station device, which receives a neighbor base station
information from a serving advanced base station (ABS) in a
broadband wireless access system, comprising: a processor; and a
radio communication (RF) module configured to transceive radio
signals with the serving advanced base station under control of the
processor, wherein the processor controls the radio communication
(RF) module to transmit a 1.sup.st message including a base station
type information to the serving advanced base station; and wherein
the processor controls the radio communication (RF) module to
receive a 2.sup.nd message including the neighbor base station
information of a type indicated by the base station type
information from the serving advanced base station in response to
the 1.sup.st message.
15. The mobile station device of claim 14, wherein the base station
type information is set to a value indicating one selected from the
group consisting of a closed subscriber group-closed femto base
station (CSG-Closed Femto ABS), a closed subscriber group-open
femto base station (CSG-Open Femto ABS) and an open subscriber
group femto base station (OSG Femto ABS), wherein the 1.sup.st
message comprises a scan reporting (AAI_SCN-REP) message, and
wherein the 2.sup.nd message comprises a neighbor advertisement
(AAI_NBR-ADV) message transmitted by unicast.
Description
TECHNICAL FIELD
[0001] The present invention relates to a broadband wireless access
system, and more particularly, to a method for an advanced mobile
station to efficiently acquire information on a neighbor legacy
base station in a mobile communication system having a legacy
system and an advanced system coexist therein.
BACKGROUND ART
[0002] Generally, handover (HO) means that a mobile station moves
away from a radio interface of one base station into a radio
interface of another base station. In the following description, a
handover procedure in a general IEEE 802.16e system is
explained.
[0003] In IEEE 802.16e network, in order to inform a mobile station
(hereinafter abbreviated MS) of information (e.g., topology) on a
basic network configuration, a serving base station (hereinafter
abbreviated SBS) is able to broadcast neighbor base station
information via a neighbor advertisement (MOB_NBR-ADV) message.
[0004] In the MOB_NBR-ADV message, contained are such system
information on a serving base station and neighbor base stations as
a preamble index, a frequency and a handover (HO)optimization
availability, DCD/UCD (downlink channel descriptor/uplink channel
descriptor) information and the like.
[0005] The DCD/UCD information contains informations that should be
known to a mobile station in order for the mobile station to
perform information communications in DL/UL (downlink/uplink). For
instance, the informations may include handover (HO) trigger
information, MAC (medium access control) version information of a
base station, MIH (media independent handover) capability
information of a base station and the like.
[0006] In a general MOB_NBR-ADV message, informations on neighbor
base stations of IEEE 802.16e type are contained. Hence,
informations of neighbor base stations of types except UEEE 802.16e
may be broadcasted to mobile stations via SII-ADV (service identity
information advertisement) message. Accordingly, the mobile station
may be able to acquire informations of a heterogeneous network base
station by making a request for a serving base station to send the
SII-ADV message.
[0007] In the following description, a procedure for a mobile
station, which has acquired information on a neighbor base station
by the above-described method, to perform a handover on IEEE
802.16e network is explained in detail.
[0008] Generally, a handover procedure on a general IEEE 802.16e
network may mainly consist of three kinds of procedures including
handover (HO) initiation & preparation, handover (HO) execution
and handover (HO) completion.
[0009] One example of a basic handover procedure, which may be
configured in the above manner, is described with reference to FIG.
1 as follows.
[0010] FIG. 1 shows one example of a handover procedure executable
in a general IEEE 802.16e system.
[0011] Referring to FIG. 1, first of all, a mobile station (MS) is
connected with a serving base station (SBS) and is then able to
perform a data exchange [S101].
[0012] The serving base station periodically broadcasts information
on a neighbor base station neighboring to the serving base station
to the mobile station via MOB_NBR-ADV message [S102].
[0013] In the course of communicating with the serving base
station, the mobile station is able to start scanning candidate
base stations (candidate HO BSs) using a handover trigger
condition. If such a handover condition as a prescribed hysterisis
margin is exceeded, the mobile station is able to make a request
for a handover procedure execution to the serving base station by
sending a handover request (MOB_MSHO-REQ) message [S103].
[0014] The serving base station is able to notify the handover
request made by the mobile station to the candidate base stations
(candidate HO BSs) contained in the MOB_MSHO-REQ message
[S104].
[0015] Each of the candidate base stations (candidate HO BSs) takes
a preemptive step for the mobile station having made the request
for the handover and is then able to deliver informations related
to the handover to the serving base station via HO-RSP message
[S105].
[0016] The serving base station is able to deliver the handover
related informations, which are obtained from the candidate base
stations (candidate HO BSs) via the HO-RSP messages, to the mobile
station via handover response (MOB_BSHO-RSP) message. In this case,
in the MOB_BSHO-RSP message, such information for performing the
handover as an action time for the handover, a handover identifier
(HO-ID), a dedicated handover (HO) CDMA ranging code and the like
can be included [S106].
[0017] Based on the information included in the MOB_BSHO-RSP
message received from the serving base station, the mobile station
is able to determine a target base station among the candidate base
stations. Subsequently, the mobile station is able to attempt a
ranging by transmitting CDMA code to the determined target base
station [S107].
[0018] Having received the CDMA code, the target base station is
able to transmit a success or failure of the ranging and physical
correction values to the mobile station via a ranging response
(RNG-RSP) message [S108].
[0019] Subsequently, the mobile station is able to send a ranging
request (RNG-REQ) message for authentication to the target base
station [S109].
[0020] Having received the ranging request message, the target base
station is able to provide the mobile station with such system
information usable by the corresponding base station as CID
(connection identifier) and the like via a ranging response message
[S110].
[0021] If the target base station successfully completes the
authentication of the mobile station and sends all update
information, it may be able to notify a success or failure of the
handover to the serving base station of the mobile station via a
handover complete message (HO-CMPT) [S111].
[0022] Thereafter, the mobile station is able to perform
information exchange with the handover performed base station
[S112].
[0023] The above-described handover process is assumed as performed
between a mobile station and a base station in accordance with IEEE
902.16e specification (e.g., WirelessMAN-OFDMA R1 Reference
System). For clarity of the following description, a system, to
which a general technology including IEEE 802.16e specification is
applied, is named `legacy system`. And, a mobile station, to which
a legacy technology is applied, is named `YMS (yardstick MS)` or a
`legacy mobile station`. Moreover, a base station, to which a
legacy technology is applied, is named `legacy base station`, `R1
BS` or `YBS (yardstick BS)`.
[0024] And, a mobile station, to which a technology (e.g., IEEE
802.16m specification: WirelessMAN-OFDMA Advanced System) further
advanced than a general technology is applied, is named `AMS
(advanced MS)` or `advanced mobile station`. And, a base station,
to which the advanced technology is applied, is named `ABS
(advanced BS)` or `advanced base station`.
[0025] YBS just has a legacy zone (hereinafter abbreviated L zone
or LZone) having a physical channel frame structure applied to a
legacy system. And, ABS supports AMS only or may support both AMS
and YMS simultaneously. In case that ABS support AMS only (e.g.,
WirelessMAC-OFDMA advanced system only), ABS just has an advanced
mobile station support zone (hereinafter named M zone or MZone)
having a physical channel frame structure applied to an advanced
system. ABS supporting both AMS and YMS (WirelessMAC-OFDMA
Reference System/WirelessMAC-OFDMA Advanced Co-existing System:
legacy supportive) may operate in mixed mode. In the following
description, this mixed mode operation is explained on the
assumption that a legacy system and an advanced system include IEEE
802.16e system and IEEE 802.16m system, respectively. ABS operating
in mixed mode has both a legacy zone and an advanced mobile station
supportive zone. An uplink (UL) region in mixed mode may be able to
operate in a manner of being divided into L zone and M zone by TDM
(time division multiplexing) or FDM (frequency division
multiplexing).
[0026] Moreover, AMS is able to receive services from ABS and YBS
both. In particular, the AMS is able to receive a service via one
of an advanced mobile station supportive zone and a legacy zone.
And, the AMS is able to perform both a handover performing process
defined in a legacy system and a handover performing process
defined in an advanced system. In the following description, this
mixed mode operation is explained on the assumption that a legacy
system and an advanced system include IEEE 802.16e system and IEEE
802.16m system, respectively.
[0027] Generally, while AMS is receiving a service in MZone of a
serving ABS capable of supporting AMD and YMS both, it may happen
that the AMS has to perform a handover into a legacy base station
or LZone of another ABS. In doing so, a process of a network
reentry into a target base station (i.e., YBS or LZone of ABS
operating in mixed mode) may follow a procedure defined in the
legacy system. Before following the defined process, it may be
necessary for the AMS to acquire information on a neighbor legacy
base station (or a legacy system supportive base station).
[0028] However, if a serving base station broadcasts information on
a neighbor YBS via a neighbor advertisement (AAI_NBR-ADV) message,
duplicative information is broadcasted from the LZone via a
neighbor advertisement (MOB-NBR-ADV) message. In particular, a list
of neighbor YBSs is broadcasted from the LZone of the ABS for YMSs.
If the list of the neighbor YBSs is broadcasted from MZone of the
ABS as well, the base station broadcasts the duplicative
information so that the mobile station receives the duplicative
information.
DISCLOSURE OF THE INVENTION
Technical Tasks
[0029] Accordingly, the present invention is directed to
substantially obviate one or more problems due to limitations and
disadvantages of the related art. First of all, an object of the
present invention is to provide a method for an advanced mobile
station to efficiently acquire system information of a neighbor
legacy base station and apparatus for performing the same.
[0030] Another object of the present invention is to provide a
method of informing an advanced mobile station of neighbor legacy
base station information efficiently and apparatus for performing
the same, by which an advanced base station can be prevented from
wasting radio resources.
[0031] Technical tasks obtainable from the present invention are
non-limited the above mentioned technical tasks. And, other
unmentioned technical tasks can be clearly understood from the
following description by those having ordinary skill in the
technical field to which the present invention pertains.
Technical Solutions
[0032] To achieve these and other advantages and in accordance with
the purpose of the present invention, as embodied and broadly
described, a method of receiving information on a neighbor base
station, which is received by an advanced mobile station (AMS) from
a serving base station operating in a mixed mode in a mobile
communication system having a legacy system and an advanced system
coexist therein, according to one embodiment of the present
invention may include the steps of receiving a 2.sup.nd message
including a 1.sup.st time information indicating a time of
broadcasting a 1.sup.st message from a 1.sup.st zone for the legacy
system of the serving base station via a 2.sup.nd zone for the
legacy system of the serving base station and receiving the
1.sup.st message from the 1.sup.st zone using the 1.sup.st time
information, wherein the 1.sup.st message includes system
information on at least one of a base station supporting the legacy
system around the serving base station and the 1.sup.st zone of a
base station operating in the mixed mode around the serving base
station.
[0033] Preferably, the 1.sup.st time information may include at
least one selected from the group consisting of an offset
information indicating the time of broadcasting the 1.sup.st
message from the 1.sup.st zone as an offset from a time of
receiving the 2.sup.nd message and an interval information
indicating an interval of broadcasting the 1.sup.st message from
the 1.sup.st zone.
[0034] More preferably, each of the offset information and the
interval information may be determined by a frame unit.
[0035] In this case, the 1.sup.st message may further include a
2.sup.nd time information indicating a time of transmitting the
system information of the 1.sup.st zone and the method may further
include the step of receiving the system information of the
1.sup.st zone using the 2.sup.nd time information.
[0036] Preferably, the legacy system may include WirelessMAN-OFDMA
R1 reference system, the advanced system may include IEEE 802.16m
system, the 1.sup.st message may include a neighbor advertisement
(MOB_NBR-ADV0 message, and the 2.sup.nd message may include an
advanced neighbor advertisement (AAI_NBR-ADV) message.
[0037] To further achieve these and other advantages and in
accordance with the purpose of the present invention, a mobile
station device, which receives information on a neighbor base
station from a serving base station operating in a mixed mode in a
mobile communication system having a legacy system and an advanced
system coexist therein, according to one embodiment of the present
invention may include a processor and a radio communication (RF)
module configured to transceive radio signals with the serving base
station under control of the processor, wherein the processor
controls the radio communication (RF) module to receive a 2.sup.nd
message including a 1.sup.st time information indicating a time of
broadcasting a 1.sup.st message from a 1.sup.st zone for the legacy
system of the serving base station via a 2.sup.nd zone for the
legacy system of the serving base station, wherein the processor
controls the radio communication (RF) module to receive the
1.sup.st message from the 1.sup.st zone using the 1.sup.st time
information, and wherein the 1.sup.st message includes system
information on at least one of a base station supporting the legacy
system around the serving base station and the 1.sup.st zone of a
base station operating in the mixed mode around the serving base
station.
[0038] Preferably, the 1.sup.st time information may include at
least one selected from the group consisting of an offset
information indicating the time of broadcasting the 1.sup.st
message from the 1.sup.st zone as an offset from a time of
receiving the 2.sup.nd message and an interval information
indicating an interval of broadcasting the 1.sup.st message from
the 1.sup.st zone.
[0039] More preferably, each of the offset information and the
interval information may be determined by a frame unit.
[0040] In this case, the 1.sup.st message may further include a
2.sup.nd time information indicating a time of transmitting the
system information of the 1.sup.st zone and the processor may
control the system information of the 1.sup.st zone to be received
using the 2.sup.nd time information.
[0041] Preferably, the legacy system may include WirelessMAN-OFDMA
R1 reference system, the advanced system may include IEEE 802.16m
system, the 1.sup.st message may include a neighbor advertisement
(MOB_NBR-ADV0 message, and the 2.sup.nd message may include an
advanced neighbor advertisement (AAI_NBR-ADV) message.
[0042] To further achieve these and other advantages and in
accordance with the purpose of the present invention, a method of
receiving a neighbor base station information, which is received by
an advanced mobile station (AMS) from a serving advanced base
station (ABS) in a broadband wireless access system, according to
another embodiment of the present invention may include the steps
of transmitting a 1.sup.st message including a base station type
information to the serving advanced base station and receiving a
2.sup.nd message including the neighbor base station information of
a type indicated by the base station type information from the
serving advanced base station in response to the 1.sup.st
message.
[0043] Preferably, the base station type information may be set to
a value indicating one selected from the group consisting of a
closed subscriber group-closed femto base station (CSG-Closed Femto
ABS), a closed subscriber group-open femto base station (CSG-Open
Femto ABS) and an open subscriber group femto base station (OSG
Femto ABS).
[0044] More preferably, the 1.sup.st message may include a scan
reporting (AAI_SCN-REP) message and the 2.sup.nd message may
include a neighbor advertisement (AAI_NBR-ADV) message transmitted
by unicast.
[0045] To further achieve these and other advantages and in
accordance with the purpose of the present invention, a mobile
station device, which receives a neighbor base station information
from a serving advanced base station (ABS) in a broadband wireless
access system, according to another embodiment of the present
invention may include a processor and a radio communication (RF)
module configured to transceive radio signals with the serving
advanced base station under control of the processor, wherein the
processor controls the radio communication (RF) module to transmit
a 1.sup.st message including a base station type information to the
serving advanced base station and wherein the processor controls
the radio communication (RF) module to receive a 2.sup.nd message
including the neighbor base station information of a type indicated
by the base station type information from the serving advanced base
station in response to the 1.sup.st message.
[0046] Preferably, the base station type information may be set to
a value indicating one selected from the group consisting of a
closed subscriber group-closed femto base station (CSG-Closed Femto
ABS), a closed subscriber group-open femto base station (CSG-Open
Femto ABS) and an open subscriber group femto base station (OSG
Femto ABS), the 1.sup.st message may include a scan reporting
(AAI_SCN-REP) message, and the 2.sup.nd message may include a
neighbor advertisement (AAI_NBR-ADV) message transmitted by
unicast.
Advantageous Effects
[0047] According to at last one embodiment of the present
invention, a mobile station acquires information for receiving a
message containing neighbor legacy base station information
broadcasted from L zone of a corresponding base station via a
message broadcasted from M zone of the corresponding base station
operating in a mixed mode and may be then able to efficiently
acquire the neighbor legacy base station information from the L
zone.
[0048] Moreover, since a neighbor legacy base station information
broadcasted via L zone may not be duplicatively contained in
broadcast information of M zone, the present invention may be able
to prevent an advanced base station from wasting radio
resources.
[0049] Effects obtainable from the present invention are
non-limited the above mentioned effect. And, other unmentioned
effects can be clearly understood from the following description by
those having ordinary skill in the technical field to which the
present invention pertains.
DESCRIPTION OF DRAWINGS
[0050] FIG. 1 shows one example of a handover procedure executable
in IEEE 802.16e system.
[0051] FIG. 2 shows one example of a procedure for an advanced
mobile station to acquire legacy base station information and a
corresponding handover procedure according to one embodiment of the
present invention.
[0052] FIG. 3 shows one example of a procedure for an advanced
mobile station to acquire legacy base station information and a
corresponding handover procedure according to one embodiment of the
present invention in aspect of relation with neighbor base
stations.
[0053] FIG. 4 shows one example of a procedure for an advanced
mobile station to acquire legacy base station information and a
corresponding handover procedure according to another embodiment of
the present invention.
[0054] FIG. 5 is a block diagram for one example of configurations
of transmitting and receiving ends according to another embodiment
of the present invention.
MODE FOR INVENTION
[0055] The following embodiments correspond to combinations of
elements and features of the present invention in prescribed forms.
And, it is able to consider that the respective elements or
features are selective unless they are explicitly mentioned. Each
of the elements or features can be implemented in a form failing to
be combined with other elements or features. Moreover, it is able
to implement an embodiment of the present invention by combining
elements and/or features together in part. A sequence of operations
explained for each embodiment of the present invention can be
modified. Some configurations or features of one embodiment can be
included in another embodiment or can be substituted for
corresponding configurations or features of another embodiment.
[0056] In this disclosure, embodiments of the present invention are
described centering on the data transmission/reception relations
between a base station and a terminal. In this case, the base
station is meaningful as a terminal node of a network which
directly performs communication with the terminal. In this
disclosure, a specific operation explained as performed by a base
station can be performed by an upper node of the base station in
some cases.
[0057] In particular, in a network constructed with a plurality of
network nodes including a base station, it is apparent that various
operations performed for communication with a terminal can be
performed by a base station or other network nodes except the base
station. In this case, `base station (BS)` can be replaced by such
a terminology as a fixed station, a Node B, an eNode B (eNB), an
access point, an advanced base station (ABS) and the like. And,
`terminal` can be replaced by such a terminology as a user
equipment (UE), a mobile station (MS), a mobile subscriber station
(MSS), and advanced mobile station (AMS), a subscriber station (SS)
and the like.
[0058] Embodiments of the present invention can be implemented
using various means. For instance, embodiments of the present
invention can be implemented using hardware, firmware, software
and/or any combinations thereof.
[0059] In case of the implementation by hardware, a method
according to each embodiment of the present invention can be
implemented by at least one selected from the group consisting of
ASICs (application specific integrated circuits), DSPs (digital
signal processors), DSPDs (digital signal processing devices), PLDs
(programmable logic devices), FPGAs (field programmable gate
arrays), processor, controller, microcontroller, microprocessor and
the like.
[0060] In case of the implementation by firmware or software, a
method according to each embodiment of the present invention can be
implemented by modules, procedures, and/or functions for performing
the above-explained functions or operations. Software code is
stored in a memory unit and is then drivable by a processor. The
memory unit is provided within or outside the processor to exchange
data with the processor through the various means known to the
public.
[0061] Embodiments of the present invention are supportable by
standard documents disclosed in at least one of wireless access
systems including IEEE 802 system, 3GPP system, 3GPP LTE system and
3GPP2 system. In particular, the steps or parts, which are not
explained to clearly reveal the technical idea of the present
invention, in the embodiments of the present invention can be
supported by the above documents. Moreover, all terminologies
disclosed in this document can be supported by the above standard
documents. Specifically, embodiments of the present invention can
be supported by at least one of P802.16-2004, P802.16e-2005,
P802.16Rev2 and IEEE P802.16m documents which are the standard
documents of IEEE 802.16 system.
[0062] In the following description, specific terminologies are
provided to help the understanding of the present invention. And,
the use of the specific terminology can be modified into another
form within the scope of the technical idea of the present
invention.
1.sup.st Embodiment
[0063] According to the present embodiment in the following
description, assume a case that AMS is receiving a service from
MZone of ABS operating in a mixed mode and that the AMS needs
information on a neighbor legacy base station for the purpose of
performing a handover into the neighbor legacy base station.
[0064] In the ABS operating in the mixed mode, system information
of a neighbor legacy base station is contained in a neighbor
advertisement (MOB_NBR-ADV) message broadcasted from LZone. Yet, in
order for the AMS receiving the service from the MZone to acquire
information on neighbor base stations including a legacy base
station, if the AMS always receives both MOB-NBR-ADV message of the
LZone and AAI_NBR-ADV message of the MZone together, it may be very
inefficient. Moreover, the MOB-NBR-ADV message of the LZone has a
relatively long transmission interval. If the AMS attempt a
reception without knowing a transmission time of the corresponding
message, it may cause an unnecessary time delay. Therefore,
according to the present embodiment, in case that LZone of a legacy
base station or ABS exists around, scheduling information of the
MOB-NBR-ADV message of the LZone is proposed to be contained in the
AAI_NBR-ADV message of the MZone. If the scheduling information of
the MOB-NBR-ADV message is contained in the AAI_NBR-ADV message, a
mobile station may be aware that the LZone of the legacy base
station or ABS exists around the mobile station.
[0065] In particular, the information on a time of sending the
MOB_NBR-ADV message may be contained in the scheduling information
of the MOB_NBR-ADV message.
[0066] The time of sending the MOB_NBR-ADV message may be contained
in the AAI_NBR-ADV message in a manner of having a format of
`neighbor advertisement offset` or `NBR-ADV offset` field. A value
of the neighbor advertisement offset field may be set by a frame
unit. In this case, it may be indicated that the MOB_NBR-ADV
message will be sent from LZone after duration of a frame amounting
to a value of the neighbor advertisement offset field after
transmission of the AAI_NBR-ADV message.
[0067] And, the transmission interval information of the
MOB_NBR-ADV message may be contained in the scheduling information
of the MOB_NBR-ADV message. In this case, the interval information
may be contained in the AAI_NBR-ADV message in a manner of having a
format of `neighbor advertisement interval` or `NBR-ADV interval`
field. This field may be set by a frame unit as well. Through this
field, if the mobile station fails in reception of the MOB_NBR-ADV
message sent from the LZone at the time according to the neighbor
advertisement offset field, the mobile station may be able to
receive the MOB_NBR-ADV message broadcasted again from the LZone
after duration of a frame indicated by the neighbor advertisement
interval field value without decoding the LZone continuously until
a next transmission interval.
[0068] According to the above-described proposal, a legacy base
station information acquiring procedure and a corresponding
handover procedure are described with reference to FIG. 2 as
follows.
[0069] In FIG. 2, assume that a legacy base station exists around a
serving ABS operating in a mixed mode.
[0070] Referring to FIG. 2, while a mobile station (AMS) enters
MZone of a serving ABS operating in a mixed mode and then performs
a data exchange [S201], the mobile station may be able to receive a
neighbor advertisement (AAI_NBR-ADV) message from the MZone of the
serving ABS [S202].
[0071] In doing so, scheduling information of the neighbor
advertisement (MOB_NBR-ADV) message of the LZone is contained in
the AAI_NBR-ADV message. The mobile station receives the
MOB_NBR-ADV message of the LZone at the time indicated by a
neighbor advertisement interval field of the scheduling information
and may be then able to acquire information on a neighbor legacy
base station [S203]. In doing so, before receiving the MOB_NBR-ADV
message, the mobile station may have received system information
(UCD/DCD) of the LZone.
[0072] Having acquired the neighbor legacy base station without
unnecessary standby time using the scheduling information of the
neighbor advertisement (MOB_NBR-ADV) message, the mobile station
may be able to attempt scanning of the legacy base station using
the acquired information [S204].
[0073] Subsequently, the mobile station determines a handover into
the legacy base station and may be then able to make a request for
the handover into the legacy base station through handover
request/command (AAI_HO-REQ/CMD) message exchanges with the serving
ABS [S205].
[0074] Thereafter, the mobile station performs a network reentry
procedure, which includes a ranging request message exchange with
the legacy base station and a response message exchange with the
legacy base station, on the legacy base station [S206, S207] and
may be then able to normally perform data exchanges with the legacy
base station [S208].
[0075] Since the above-mentioned steps S206 to S208 are similar to
the former steps S107 to S112 described with reference to FIG. 1,
their duplicative details shall be omitted for clarity of the
following description.
[0076] In the following description, when various base stations
exist around, a process for acquiring legacy base station
information and a process for performing a handover are explained
with reference to FIG. 3.
[0077] FIG. 3 shows one example of a procedure for an advanced
mobile station to acquire legacy base station information and a
corresponding handover procedure according to one embodiment of the
present invention in aspect of relation with neighbor base
stations.
[0078] In FIG. 3, assume that a mobile station (AMS) is receiving a
service from MZone of a serving ABS operating in a mixed mode and
that a legacy base station (BSID=2), an ABS (BSID=3) operating in a
mixed mode and a 16m only ABS (BSID=4) exist around the serving
ABS. Moreover, if the AMS performs a handover into a legacy base
station, assume that the AMS performs a fast handover provided by a
general IEEE 802.16 system.
[0079] Referring to FIG. 3, while a mobile station (AMS) is
receiving a service from MZone of a serving ABS operating in a
mixed mode [S301], it may be able to receive a neighbor
advertisement (AAI_NBR-ADV) message from the MZone of the serving
ABS [S302].
[0080] In this case, in the AAI_NBR-ADV message, MZone information
of the ABS having the BSID set to 3, information on the ABS having
the BSID set to 4 and scheduling information of the neighbor
advertisement (MOB_NBR-ADV) message broadcasted from the LZone are
contained. The mobile station receives the MOB_NBR-ADV message of
the LZone at the time indicated by a neighbor advertisement
interval field of the scheduling information and may be then able
to information on a neighbor legacy base station without
unnecessary standby time [S303]. In doing so, in the MOB_NBR-ADV
message, LZone information of the ABS having the BSID set to 3 and
information on a legacy base station having the BSID set to 2 may
be contained. Moreover, before receiving the MOB_NBR-ADV message,
the mobile station may have received system information (UCD/DCD)
of the LZone in advance.
[0081] Having acquired the neighbor base station information via
the MOB_NBR-ADV message and the AAI_NBR-ADV message, the mobile
station may make a request for performing a scanning to the serving
ABS in order to perform a scanning on neighbor base stations [S304]
and may then receive scanning related information such as a
scanning interval and the like in response to the scanning request
[S305].
[0082] Using the acquired scanning and neighbor base station
related informations, the mobile station may be able to attempt the
scanning of the neighbor base stations including the legacy base
station [S306].
[0083] Subsequently, the mobile station triggers a handover in
accordance with a prescribed handover triggering condition [S307]
and may then send a handover request (AAI_HO-REQ) message to the
serving ABS [S308]. In doing so, via the handover request message,
the mobile station may inform the serving ABS that a desired target
base station is the legacy base station.
[0084] Correspondingly, the serving ABS exchanges information on
the mobile station and the handover related information with the
legacy base station (or candidate base stations including the
legacy base station) via backbone network messages. In doing so,
the legacy base station may inform the serving ABS of a dedicated
ranging code (herein assumed as `x`) for the fast handover. Having
received the handover related information from the legacy base
station, the serving ABS delivers information on the candidate base
station to the mobile station via a handover command (AAI_HO-CMD)
message [S309]. In doing so, in the handover command message, the
dedicated ranging code information delivered from the legacy base
station is contained.
[0085] The mobile station determines the handover into the legacy
base station (BSID=2) and then transmits a dedicated ranging code
to the legacy base station [S310]. In doing so, the transmission of
the ranging code may be performed at the time indicated by an
action time field contained in the AAI_HO-CMD message.
[0086] Having received the dedicated ranging code, the legacy base
station may be able to transmit a failure or success of the ranging
and physical correction values to the mobile station via a ranging
response (RNG-RSP) message [S311].
[0087] Subsequently, the mobile station may be able to send a
ranging request (RNG-REQ) message to the legacy base station
[S312].
[0088] Having received the ranging request message, a target base
station may be able to provide the mobile station with such system
information usable for the corresponding base station as a
connection identifier (CID) and the like via a ranging response
message [S313].
[0089] Thereafter, the mobile station performs the rest of the
network reentry procedure and may be then able to normally perform
a data exchange with the legacy base station [S314].
[0090] Meanwhile, according to another embodiment, it may be
proposed that information on a time of transmitting system
information of LZone is further included in scheduling information
of MOB_NBR-ADV message.
[0091] In order for a mobile station to receive a neighbor
advertisement message broadcasted from LZone, it may be necessary
to acquire system information (i.e., DCD/UCD) of the LZone in the
first place. This is because a system information of a
corresponding base station and a system information (i.e., delta
information) of a neighbor base station, which is different from
the information of the corresponding base station, are included in
the MOB_NBR-ADV message. And, the AMS needs to know the system
information of the LZone to receive the MOB_NBR-ADV message. In
doing so, the information on the transmission time of the system
information of the LZone preferably indicates a transmission time
of DCD/UCD which is transmitted prior to the MOB_NBR-ADV message
indicated by a neighbor advertisement offset field. In this case,
the AMS receives the system information of the LZone at the time
indicated by the information on the transmission time of the system
information of the LZone and may be then able to receive the
MOB_NBR-ADV message of the LZone at the time indicated by the
neighbor advertisement offset field.
2.sup.nd Embodiment
[0092] According to another embodiment of the present invention,
while a mobile station (AMS) is receiving a service from an advance
base station (16m-only ABS) which does not support a legacy, a
method of requesting information on a neighbor legacy base station
to a serving base station and receiving the requested information
by unicast is proposed. A neighbor base station information
acquiring method according to the present embodiment is described
with reference to FIG. 4 as follows.
[0093] FIG. 4 shows one example of a procedure for an advanced
mobile station to acquire legacy base station information and a
corresponding handover procedure according to another embodiment of
the present invention.
[0094] Referring to FIG. 4, while a mobile station (AMS) is
receiving a service via a serving advance base station (ABS)
[S401], it may be able to request for information (e.g., neighbor
base station list) on a neighbor legacy base station to the serving
ABS [S402]. In doing so, the request for the legacy base station
information may be performed via a newly defined medium access
control (MAC) management message. Moreover, a base station type
information (Neighbor_Request_BS_Type) field is included in the
corresponding message and a value of the corresponding field may be
set to a value indicated by the legacy base station.
[0095] Hence, the serving ABS may be able to transmit the legacy
base station information requested by the mobile station to the
mobile station in form of a unicast MAC message [S403].
[0096] Using the acquired legacy base station information, the
mobile station performs a scanning on the legacy base station
[S404]. The mobile station may be then able to perform a handover
into the corresponding legacy base station [S405 to S408].
[0097] Since the steps S405 to S408 shown are similar to the former
steps S205 to S208 described with reference to FIG. 2,
respectively, their duplicative details shall be omitted for
clarity of the following description.
[0098] Meanwhile, the aforementioned base station type information
(Neighbor_Request_BS_Type) may indicate a type of a femto base
station instead of indicating whether the legacy base station is an
advanced base station. For instance, if types of a femto base
station are categorized into a closed subscriber group-closed femto
base station (CSG-Closed Femto ABS), a closed subscriber group-open
femto base station (CSG-Open Femto ABS) and an open subscriber
group femto base station (OSG Femto ABS), at least one group may be
indicated by the base station type information.
[0099] Moreover, instead of a new MAC management message, it may be
able to use a previous MAC message. For instance, in order to
request a neighbor base station information, it may be able to use
a scan reporting (AAI-SCN-REP) message. For another instance, in
order to deliver a neighbor base station information to a mobile
station, it may be able to use a neighbor advertisement
(AAI_NBR-ADV) message sent by unicast.
[0100] Therefore, a mobile station specifies a type of a femto base
station via a base station type information of AAI_SCN-REP message
and may be then able to make a request for an information (list) of
a neighbor femto base station to a serving ABS. In response to the
request, a base station may be able to send AAI_NBR-ADV message
including the information (list) of the femto base station of the
corresponding type to the mobile station by unicast.
[0101] Configurations of Mobile and Base Stations
[0102] In the following description, a mobile station and a base
station (FBS or MBS) for implementing the above-mentioned
embodiments of the present invention according to another
embodiment of the present invention are explained.
[0103] First of all, a mobile station may work as a transmitter in
uplink or may work as a receiver in downlink. A base station may
work as a receiver in uplink or may work as a transmitter in
downlink. In particular, each of the mobile station and the base
station may include a transmitter and a receiver for transmission
of information and/or data.
[0104] Each of the transmitter and the receiver may include a
processor, a module, a part and/pr a means for performing
embodiments of the present invention. In particular, each of the
transmitter and the receiver can include a module (means) for
encrypting a message, a module for interpreting the encrypted
message, an antenna for transceiving the message and the like. One
example of the transmitting and receiving ends is described with
reference to FIG. 6 as follows.
[0105] FIG. 5 is a block diagram for one example of configurations
of transmitting and receiving ends according to another embodiment
of the present invention.
[0106] Referring to FIG. 5, a left part of the drawing represents a
configuration of a transmitting end, while a right part of the
drawing represents a configuration of a receiving end. Each of the
transmitting and receiving ends may include an antenna 5/10, a
processor 20/30, a transmitting module (Tx module) 40/50, a
receiving module (Rx module) 60/70 and a memory 80/90. In this
case, the respective components may perform corresponding
functions. The respective components are described in detail as
follows.
[0107] First of all, the antenna 5/10 externally transmits a signal
generated from the transmitting module 40/50. And, the antenna 5/10
receives a radio signal from outside and then delivers the received
radio signal to the receiving module 60/70. In case that a
multiple-antenna (MIMO) function is supported, at least two
antennas may be provided.
[0108] The antenna, the transmitting module and the receiving
module may be integrated into a radio communication (RF)
module.
[0109] The processor 20/30 generally controls overall operations of
a mobile terminal. In particular, the processor 20/30 may be able
to perform a control function for performing the above-described
embodiments of the present invention, a MAC (medium access control)
frame variable control function according to service
characteristics and propagation environment, a handover function,
an authentication function, an encryption function and the like. In
particular, the processor 20/20 may perform overall controls to
perform the handover through the zone switching shown in FIGS. 2 to
4.
[0110] In more particular, the processor of the mobile terminal
(AMS) acquires scheduling information of MOB_NBR-ADV message
included in AAI_NBR-ADV message received from MZone of ABS
operating in a mixed mode, receives the MOB_NBR-ADV message of
LZone at the time indicated by the scheduling information, and may
control neighbor legacy base station information to be
acquired.
[0111] Besides, the processor of the mobile station may be able to
perform overall control operations of the operating steps disclosed
in the aforementioned embodiments.
[0112] The transmitting module 40/50 performs prescribed coding and
modulation on a signal and/or data, which is scheduled by the
processor 20/30 and will be then transmitted externally, and is
then able to deliver the coded and modulated signal and/or data to
the antenna 10.
[0113] The receiving module 60/70 reconstructs the radio signal
received externally via the antenna 5/10 into original data in a
manner of performing decoding and demodulation on the received
radio signal and is then able to deliver the reconstructed original
data to the processor 20/30.
[0114] The memory 80/90 may store programs for the processing and
control of the processor 20/30 and is able to perform a function of
temporarily storing input/output data. And, the memory 80/90 may
include at least one of storage media including a flash memory, a
hard disk, a multimedia card micro type memory, a memory card type
memory (e.g., SD memory, XD memory, etc.), a RAM (random access
memory), an SRAM (static random access memory), a ROM (read-only
memory), an EEPROM (electrically erasable programmable read-only
memory), a PROM (programmable read-only memory), a magnetic memory,
a magnetic disk, an optical disk and the like.
[0115] Meanwhile, the base station may perform a controller
function for performing the above-described embodiments of the
present invention, an OFDMA (orthogonal frequency division multiple
access) packet scheduling, TDD (time division duplex) packet
scheduling and channel multiplexing function, a MAC (medium access
control) frame variable control function according to a service
characteristic and electric wave environment, a fast traffic
real-time control function, a handover function, an authentication
and encryption function, a packet modulation/demodulation function
for data transmission, a fast packet channel coding function, a
real-time modem control function, and the like using at least one
of the modules mentioned in the foregoing description and may
further include means, modules, parts and/or the like to perform
these functions.
[0116] While the present invention has been described and
illustrated herein with reference to the preferred embodiments
thereof, it will be apparent to those skilled in the art that
various modifications and variations can be made therein without
departing from the spirit and scope of the invention. Thus, it is
intended that the present invention covers the modifications and
variations of this invention that come within the scope of the
appended claims and their equivalents. And, it is apparently
understandable that an embodiment is configured by combining claims
failing to have relation of explicit citation in the appended
claims together or can be included as new claims by amendment after
filing an application.
INDUSTRIAL APPLICABILITY
[0117] Accordingly, a more efficient neighbor legacy base station
information acquiring method in a broadband wireless access system,
a handover performing procedure using the same and a device
configuration for the same are described with reference to the
examples applied to IEEE 802.16m system and may be applicable to
various mobile communication systems including 3GPP/3GPP2 and the
like as well as IEEE 802.xx systems.
* * * * *